View source for Properties of cyclic quadrilateral

===Objectives===
*In a cyclic quadrilateral the sum of opposite interior angles is 180 degrees.
*In a cyclic quadrilateral the exterior angle is equal to interior opposite angle
===Estimated Time===
45 minutes

===Prerequisites/Instructions, prior preparations, if any===
* Circles and quadrilaterals should have been covered.

===Materials/ Resources needed===
Coloured paper, pair if scissors, sketch pen, carbon paper, geometry box

This activity has been taken from the website http://mykhmsmathclass.blogspot.in/2007/11/class-ix-activity-16.html

[[File:c.q.jpeg|300px|link=http://karnatakaeducation.org.in/KOER/en/index.php/File:C.q.jpeg]]

===Process (How to do the activity)===
Note: Refer the above geogebra file to understand the below mentioned labelling.,br>
# Draw a circle of any radius on a coloured paper and cut it.
# Paste the circle cut out on a rectangular sheet of paper.
# By paper folding get chords AB, BC, CD and DA in order.
# Draw AB, BC, CD & DA. A cyclic quadrilateral ABCD is obtained.
# Make a replica of cyclic quadrilateral ABCD using carbon paper.
# Cut the replica into 4 parts such that each part contains one angle .
# Draw a straight line on a paper.
# Place angle BAD and angle BCD adjacent to each other on the straight line.Write the observation.
# Place angle ABC and angle ADC adjacent to each other on the straight line . Write the observation.
# Produce AB to form a ray AE such that exterior angle CBE is formed.
# Make a replica of angle ADC and place it on angle CBE . Write the observation.
* '''Developmental Questions (What discussion questions)'''
# How do you take radius ?
# What is the circumference ?
# What is a chord ?
# What is a quadrilateral ?
# Where are all four vertices of a quadrilateral located ?
# What part are we trying to cut and compare ?
# What can you infer ?
* '''Evaluation  Questions'''  
# Angle BAD and angle BCD, when placed adjacent to each other on a straight line, completely cover the straight angle.What does this mean ?
# Angle ABC and angle ADC, when placed adjacent to each other on a straight line, completely cover the straight angle.What can you conclude ?
# Compare angle ADC with angle CBE. 
# Name the two properties of cyclic quarilaterals.
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